Various approaches have been taken to the transportation of invalids up and down stairways. Some of these are set out in U.K. Pat. No. 1,546,130 in the description of the prior art proposals. While fixed on site lifts have been proposed, few of them have actually been installed. It has therefore been necessary, for the invalid to carry his/her own motorized wheelchair carrier in the trunk of the automobile for such assembly at the building site.
One such carrier is shown in U.K. Pat. No. 1,546,130 and comprises a base assembly and handle assembly connectable to the base assembly. The base assembly comprises an endless track motion system comprising at least one belt guided around a starlike arrangement of rolls mounted on respective arms, carried by a free revolving hub. The inventor claims not only superior performance at the beginning of the climb, during the climb and termination of the climb, but also during any descent. However, because of the complicated starlike track supporting arrangement, there is a lack of support of tread in both climbing areas (See for example, FIG. 4 of that patent), the device is not satisfactory for carrying out a safe stair climbing operation, and has not been widely accepted by the public.
Another carrier employs one large roller in place of the starlike arrangement about which the endless rubber track is entrained. However, this device also lacks the back-up support for the track and is not effective, particularly when the first step is higher than the radius of the roller plus the track passing around the roller. Additionally, when the carrier engages the bottom stair, the invalid passenger is jarred.
Furthermore, each of the devices must be disassembled for transportation and easily reassembled for safe operation in all instances. However, in this regard, the prior art proposals have not been entirely satisfactory and the passenger safety could not be insured. For example, in emergencies, the locking assembly must guarantee the absolute security of the invalid.
It is therefore an object of this invention to provide wheelchair carriers for climbing stairways, which in various forms, are easily assembled and disassembled, secure during all aspects of their operation, and which provide a smooth ride for the passenger and which brake quickly and efficiently in emergencies.
Further and other objects of the invention will be realized by those skilled in the art from the following summary of the invention and detailed description of a preferred embodiment thereof.